Microtelephone.



o. 793.444. PATENTED JUNE 27, 1905. K. HUFLINGER.

MIGROTELEPHONE.

APPLIGATION FILED MAB. 11,1904.

Nrrnn STATES Patented June 27, 1905.

KONRAD HOFLINGER, OF VIENNA, AUSTRIA-HUNGARY, ASSIGNOR OF ONE-HALF TOCARL WOLFFHARDT, JR, OF VIENNA, AUSTRIA- HUNGARY.

IVIICROTELEPHONE.

SPECIFICATION forming part of Letters Patent No. 793,444, dated June 27,1905. Application filed March 11, 1904. semi No. 197,626.

To all whmn it may concern.-

Be it known that I, KoNRAD HOFLINGER, mechanician, asubject of theEmperor of Austria-Hungary, residing at No. 66 Schonbrunnerstrasse V,Vienna, Austria-Hungary, have invented certain Improvements in andRelating to Microtelephones; and Ido hereby declare the following to bea full, clear, and exact description of the in vention,such as willenable others skilled in the art to which it appertains to make and usethe same, reference being bad to the accompanying drawings, and tonumerals of reference marked thereon, which form a part of thisspecification.

This invention has for its object an apparatus in which a microphone anda telephone are combined in a suitable manner so as to form a singleapparatus. The arrangement of the two appliances is such that themicrophone is mounted behind the telephone in the same case, so that acompact and handy form is given to the apparatus as a whole, thusfacilitating its mounting. In addition to this the invention comprisesseveral novel arrangements by means of which the calling-key, alarmdevice, &c., may all be combined with the same casing.

A constructional form of the invention is steel magnets 2 withpole-pieces 3 and magnet-windings 4 4". The diaphragm 5 is arranged infront of the poles of the magnet in the known manner.

As is more particularly shown in Fig. 4, the microphone is arranged inthe lower or inner part of the casing 1. In the constructional form hererepresented the microphone consists of a carbon electrode 6 withcircular aperture, in front of which a carbon diaphragm 7 is arranged.The aperture in the carbon electrode 6 is filled with small balls ofcarbon 8.

For the purpose of permitting the soundwaves to act more effectuallyupon the carbon diaphragm the wall of the casing 1 is provided wit-hopenings 9 between the telephone and microphone plate.

To make use of the apparatus, it is applied, with the sound-opening 10,to the ear in the usual manner. essary to remove the apparatus from theear, but only to speak in the ordinary manner, the sound-waves beingtransmitted both by the air and by the bones of the skull to theapparatus.

The apparatus has proved very eflicient in action and particularlyitpresents the advantage that other sounds produced in proximity to theapparatus, such as hammering and the like, are hardly received by theapparatus at all or transmitted to the other station.

In order to permit of using the apparatus as a table-telephone withoutauxiliary appliances, it is formed in the following manner: Two feet 11are fixed to the base-plate. In addition to this a push button 12, whichserves as a third foot, is passed through the base-plate and by means ofthis push a spring 13, arranged in the annular space around themicrophone, may be pressed against a pin 14, thereby closing a circuitfor calling the other station. When the apparatus stands with its twofeet 11 and the push-button 12 upon the table, as shown in Fig. 1, thenby means of the push button 12 the spring 13 may be pressed against thepin 14 by hand-pressure above upon the apparatus, thus pushing button 12into the apparatus.

If the apparatus is to be operated by battery-current alone, withoutinduction-coil, which is perfectly satisfactory for short distances, itis possible to employ the diaphragm itself as calling device. To thisend a spring- In order to talk, it is not necarm 15, provided with aplatinum contact 16, is attached to the diaphragm. To the baseplate 17below the telephone is attached a bracket 18, with'adjustablecontact-screw 19. Under the action. of the magnet there is a tendency inthe diaphragm to bulge inward. This changes the plane of the portion ofthe diaphragm which carries spring-arm 15, and although the movement ofsaid portion is but slight it results in a sufiicient movement at theother end of the spring-arm 15 to cause a break of contact between parts15 and 19. The connections are such that upon calling up at one stationthe current flows through the windings 4: of the telephone and thecontacts 16 19 to the other station, so that the diaphragm isintermittently attracted and released, and sointermittently breaks andmakes contact at the points 19 and 16, producing a loud sound.

In order to switch off the alarm device and switch in the microphone, soas to use the apparatus for conversation, the contact-spring 20 ismounted in the casing in such a manner that it may be actuated by meansof the pushbutton 21, projecting from the side of the casing. Thiscontact-spring normally bears upon the pin 22, which is connected withthe interrupter-contactof thediaphragm. When, however, the push-button21 is pressed, the spring comes against the contact-arm 23, connectedwith the microphone-carbon 6, and thus switches in the microphone. Thediagrammatic view of the electrical connections, Fig. 5, illustrates, byway of example, a method of connection by means of which two stationsmay be operated by one battery only. The two stations are not connectedthe same, but in such a way that the conductor 24 contains the battery25, and of the two other conductors 26 and 27 the one, 26, serves forcalling the right-hand station, while the other,

27, serves for calling the left-hand station. Conductors 26 and 27 servewith conductor 24 for talking. For this purpose conductor 26 runs fromspring 13 of the left-hand station to the contact-point 19 of theright-hand station. At the closing of the circuit by spring 13 thebattery 25, coils 4:, and diaphragm 5 are connected in series. At theright-hand 1. The combination of a hollow casing and a telephone and amicrophone arranged therein, the former in front of the latter, saidcasing being open to the admission of soundwaves between the telephoneand microphone, and a wall interposed in the casing between its openportion and the telephone, substantially as described.

2. The combination of a source of electric energy, a main circuitcomprising said energy source, an electromagnet in said circuit, adiaphragm operatively disposed with reference to said electromagnet toform therewith a telephone-receiver, contacts normally disposed to forman interrupter and one of them being carried by the diaphragm, a branchconductor comprising the other of said contacts, and means for closing acircuit comprising said branch conductor and the portion of the maincircuit which includes the energy source, substantially as described.

3. The combination of a casing, a telephone-receiver in said casing, amicrophone in said casing, and a plurality of feet for supporting saidcasing, one of said-feet being yieldable in the casing and constitutinga circuit-closer, substantially as described.

4. The combination of a casing, an alarm device in said casing, amicrophone in said casing, and means in said casing forsimultaneouslyswitchingin the microphone and switching out the alarmdevice, and vice versa, substantially as described.

In testimony that 1 claim the foregoing I have hereunto set my hand this24th day of February, 1904.

KONRAD HOFLINGER.

Witnesses:

WENZEL SINKY, ALVESTO S. HOGUE.

